Marauders do 10 damage to marines and have almost twice the cooldown... so in 'normal condition' or under stim-pack they do similar damage to each other. Marines have 45 HP (55 with upgrade) instead of 125 and costs 50 + 12.5 supply = 62.5 instead of 100 + 25 supply + 25 gas = 150.

If we take mineral/gas cost into account, the amount of marines will be usually 2.5 bigger than marauders (X marauders against 2.5X marines), with approximately similar amount of HP to kill each group.

The difference I see is concussive shells. X marauders can constantly 'slow down' X marines, and slowed marines will do half as much damage. So 'actually', if we consider DPS we will have X marauders against 2X marines, which is significantly more(turns out this information was wrong).

Could you please clarify why Team Liquid consider marauders weak against marines?

please don't create a bunch of new tags needlessly, and there is no need to put starcraft 2 in the title if it is in the tags..
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Jeff Atwood♦Jan 18 '11 at 23:34

Sorry, but why? What you have against 'marine' or 'marauder' tags? For me it is pretty useful. For now if somebody want to see everything about Terran he will go to "terran" tag. The same will apply for other game features. Did I create harmless tags? Don't think so. So, please, return tags back.
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BuddaJan 19 '11 at 2:49

Please see this meta-post for some tips on how to effectively tag your questions. In particular, the points about how tags should stand on their own and how new tags should not be created needlessly seem relevant to your view. Remember that the main point of tags is not for searching, but rather for filtering site content on subjects that you find interesting and subjects that you don't. The use of a tag like [tvt] for this cause is minimal and unclear to those who don't play SC2.
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ManaJan 19 '11 at 14:42

So the Marine has about 3.5 times as much effective dps.
For the Marauder to win out against the Marine you'd need at least 3.5 times as much HP.

The Marauder to Marine ratio is 125 / 45 = 2.7

Ultimately, the opinion on TeamLiquid has almost nothing to do with this calculus and everything to do with real world experience. In real world scenarios groups of Marines beat out Groups of Marauders, not only because the Effective DPS ratio is higher than the Hit Point ratio, but also because Marines take up less space; this means that more Marines will be able to attack at the same time. Ultimately that math trumps just about any theory crafting you and I could perform.

Note, that in Marauder vs Marine, Marines only do 5 damage, which reduces their effective dps to 11.6, and the dps ratio to 2.8. While this still gives the advantage to the Marines, it is paltry compared to the size advantage.

Note, that in Marauder vs Marine, Marines only do 5 damage, which reduces their effective dps to 11.6, and the dps ratio to 2.8. While this still gives the advantage to the Marines, it is paltry compared to the size advantage.
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tzenesJan 18 '11 at 18:04

+1: The space thing is, and always has been, huge in SC. Next time you're attacking with a horde of ranged units, watch how they form their arc. Marines are better than Hydras are better than Stalkers purely because of the time it takes them to arc out.
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SatanicpuppyJan 18 '11 at 18:57

1

@Satanic I've written about arcs before and their importance. I can think of few things more valuable.
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tzenesJan 18 '11 at 19:02

Tzenes, good answer. Thanks a lot! but could you please edit you answer to reflect the fact that marines do 5 damage to marauders, not 6?
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BuddaJan 18 '11 at 19:11

The top post is excellent, but a few more things that are missed here.

1) Marines build faster. This has very large ramifications, especially when considering the ability to replenish an army.

2) Gas is worth more per unit then minerals.

3) It is easier (cost wise) to inject tanks and other supporting units in to a marine army, while you will have to cut more in the way of marauders (due to gas restrictions) in order to get the same effect.

I believe he took gas being worth more per unit then minerals. Notice the Gas * 2.5 is his calculation for effective dps.
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Sadly NotJan 18 '11 at 22:49

Gas is worth more than that. Consider- the minerals/minute of a full mining base for Terran is nearly a thousand, but the gas/minute is just 240 or so. That makes gas worth four times as much as minerals. In addition, I would say that Marines can be produced from an unaltered barracks being an important factor.
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DeadMGJan 19 '11 at 1:11

@DeadMG if you look at it from how fast it can be fined then yes, gas is worth more than 2.5x, but what's more important is what it's worth in terms of what you can make with it (which is more of a soft number). I don't know how they came up with 2.5x but that seems to be about the accepted ratio in the SC2 community. In most scenarios I'd happily trade 250 gas for 1000 minerals any day.
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Davy8Jan 19 '11 at 14:59

You have to consider that Marauder have projectiles and Marines do instant damage. This might seem insignificant, but it adds up.

For the arguments sake I assume you do not have the shield upgrade, this would also work otherwise.

While missile attacks can "overkill" an unit, thus wasting DPS, instant attacks just "kill" the unit. e.g. 10 Marauders shoot at the same time at 1 Marine dealing 100 damage, but you need only 45 damage to kill the Marine, thus you loose 55 damage.

On the other hand 30 marines shoot at 1 Marauder, dealing 126 damage with 9 doing nothing (potentially shooting at another Marauder). They just waste 1/126 damage.

This might seem insignificant, but Marauders shoot slow and you cannot effectively prevent them from doing this. So basically Marines profit from focus fire, but Marauders do not and focus fire is very beneficial in a battle.

Even if you are able to micro Marauders perfectly, you lose at least 5/50 damage (10%), because Marines have only 45 health.

If this is not enough it gets worse with upgrades. Assuming you could build 3 Marines instead of 1 Marauder resource wise at +1 upgrades 30 Marines deal +30 damage, while 10 Marauders deal only +10. It gets even worse für +2 and +3 upgrades.